F@stSheet Ent-1005

Choosing a Termite Treatment Chemical IN THIS FASTSHEET RESULTS OF TERMITICIDE EVALUATIONS SAFETY ISSUES SELECTING A COMPANY FOR MORE INFORMATION

You've decided to have your home treated with a soil-applied insecticide for termites.   After talking to three pest control firms you discover that each uses a different termite treatment chemical (termiticide). Each claims their treatment chemical is the best. How do you decide?

Until now there's been little objective information about the persistence of termiticides in Texas soils. Previous studies by the U.S. Department of Agriculture were conducted outside of Texas, under very different soil and climate conditions. Ongoing research at Texas A&M University has provided the first objective comparisons of termite control chemicals for our state. The research was conducted at five sites in Texas: Lubbock, Dallas, Overton (northeast Texas), College Station, and Corpus Christi.   Each of the sites represents a different soil type and climate.  To help you understand some of the differences in the different termite control chemicals, the highlights of this research are presented below.

RESULTS OF TERMITICIDE EVALUATIONS
For all termiticides tested, chemical breakdown due to natural processes was relatively rapid, with the most significant losses of treatment chemicals occurring within the first year. After five to seven years, only small percentages of the original termiticides remained in the soil at all sites. Breakdown appears to be most pronounced in clay soils with high pH and high organic matter content (e.g., the highly alkaline blackland soils of the Dallas area). Despite significant chemical losses, however, results show that termite control chemicals still can provide your home with good termite protection.  Most termiticides, when applied correctly and properly maintained, should provide your home with a termite-proof barrier for at least three years.

No termiticide was clearly superior in with respect to persistence in the soil.   Table 1 summarizes the test results for all tested products.  The different termiticides degraded at significantly different rates depending on location; some products persisted longer at some sites compared to others. 

A termiticide should not be selected solely on the number of years of effective life.   Longevity is only one component of an effective soil termiticide.  To some people, low odor is an important factor in selecting a product.  Most of the products on the market today result in little odor during and following application.  Some people are able to detect odors of some formulations of chlorpyrifos following an application.  This more likely to occur if the application is made to wet soils.  

Another characteristic of termiticides is repellency.  Some termiticides are highly repellent to termites--others are not. Pyrethroid insecticides, such as bifenthrin, cypermethrin, fenvalerate, and permethrin, are highly repellent to most insects, including termites.  Because of this, termites rarely enter the treated zone long enough to be killed by the insecticide. Other products are less repellent and kill most termites that enter the treatment barrier.  Both types of termiticides can provide effective barriers to termite entry, however there is some evidence that termiticides with lower repellency may make it more difficult for termites to locate gaps or untreated portions of soil in the treatment zone.  Research is ongoing to see if less-repellent termiticides are more effective under actual field conditions than repellent termiticides.  

When deciding on the best treatment chemical for your home, consider the pros and cons of each product.  Ask your pest control company which product they prefer and why.  Because of the rapid rate at which most termiticides break down in the soil, request that the highest label rate be used.  By using the highest label rate you increase the effective life of the termite treatment.  When comparing prices ask for estimates based on standard and high rates of application so you are sure that you know what the quote covers, and make sure the technician applying the treatment is aware of the rate you requested. 

Table 1. Technical information and years of effective life of termiticides (based on years until minimum effective threshold concentration reached in soil analyses and bioassays). Texas A&M University, 1991-98.

* LD₅₀ is a safety rating perfomed on all registered insecticideds to compare the relative toxicities of different chemicals.  The lower the LD₅₀ value, the higher the toxicity.  Values of 0-50 are considered highly toxic; 50-500, moderately toxic; and greater than 500, low toxicity.  All LD₅₀ values expressed here are for undiluted, technical meaterials.  Actual termiticide formulations and mixtures used in termite treatments are generally much less toxic.   LD₅₀ values taken from Agricultural Chemicals Book I, W.T. Thompson, 1994.

** Fipronil is a relatively new compound and longevity results are incomplete.

SAFETY ISSUES
Termite control is one of the safest forms of pest control that can be performed in your home. Termiticides are placed under low pressure directly into the soil. When applied correctly, registered termiticides pose little risk to occupants of the home; although your termite control service may ask you to leave the structure during application as an added precaution. Once dry, termiticides generally stay where they are applied. Under most conditions, when label directions are followed, there is little risk of pesticide leaching into groundwater or streams.

SELECTING A COMPANY
When it comes to termite control, the most important decision is selecting the company you want to do the job. A careful and thorough termiticide application is always better than a hastily performed, incomplete treatment--regardless of the product used. Check over the warranty carefully. Warranties should extend for at least a year and should offer you the option of extended coverage for several years.

FOR MORE INFORMATION
For more information about termites and their control, contact your local county Extension office and ask for Extension publications B-6080, Subterranean Termites, and Internet Factsheet ENT-1006, Commonlv Asked Questions about Termite Control.  For more tips and information on selecting a termite control company, see Extension publication L-1785, How to Select a Termite Control Service.

Authors:
Michael Merchant, Ph.D., Urban Entomologist, Texas AgriLife Extension Service
Roger Gold, Ph.D., Professor, Department of Entomology, Texas A&M University

Publication information:
This publication is part of the House & Landscape Pest Series produced by the Department of Entomology, Texas A&M University, College Station, TX 77843-2475. The most recent update can be found at: http://165.95.73.17/FastSheets/Ent-1005.html